A wide variety of pin and socket contacts are known, and have a similar variety of active structures which must mechanically cooperate to give an adequate surface area of electrical contact, as well as provide mechanical holding integrity. It is relatively easy to satisfy these goals in a connector of sufficient size where the material strengths are adequate. However for very small female contacts which are smaller than about 1/2 inch in length and have to exist in a densely packed area, have very small magnitude of the other dimensions, which may be much less than 1/8 of an inch. Smaller dimensioning translates into thinner material, and the goals of small size and strength are more difficult to achieve.
The electrical contact within a socket connector is insured by the use of a spring member to bear against the male member when inserted into the socket. The spring member may be provided separately or extend from the front mouth of the socket. In both cases, and especially where the socket and pin are small, the male pin member might be inadvertently wedged behind the spring member rather than against the side of the spring member intended for contact.
This unintended wedging action can destroy the spring member, and the socket contact if the wedging is violent enough. Even where the wedging is not violent, where the spring member is bent across the mouth of the contact, the contact becomes unusable. Further poking with the male contact will further damage the contact, and the technician, if available, will have to spend significant time replacing the contact, since repair of the contact, even if it were possible, would not leave it in a reliable condition.
Where a female socket contact consists of three walls and uses the fourth wall, opposing the middle of the three walls, as its spring contact, the chances for jamming are significant. In today's zero defects environment, the miniaturization of contacts is limited by this type of significant failure rate.
What is therefore needed is a contact which is inexpensive, has high reliability generally, good contact and especially which forestalls the possibility of inadvertent insertion of the pin behind the spring member.